docs: def _cov_for(self, imls):
          """
          Clip `imls` to the range associated with the support of the
          vulnerability function and returns the corresponding
          covariance values by linear interpolation. For instance
          if the range is [0.005, 0.0269] and the imls are
          [0.0049, 0.006, 0.027], the clipped imls are
          [0.005,  0.006, 0.0269].
          """
          return self._covs_i1d(
              numpy.piecewise(
                  imls,
                  [imls > self.imls[-1], imls < self.imls[0]],
                  [self.imls[-1], self.imls[0], lambda x: x]))